1. Field of the Invention
This relates to a lock slider for a slide fastener, and more particularly to a lock slider composed of a pull tab with locking pawls, and a slider body, which are simultaneously molded in an assembled form.
2. Description of the Related Art
As shown in FIG. 10 of the accompanying drawings, Japanese Utility Model Publication No. Sho 51-4809 discloses a conventional lock slider, for a slide fastener, in which a slider body has centrally in its upper surface a rearwardly opening pull-tab-receiving groove 12' in which a pull tab 2' is to be received in such a manner that the upper surface of the pull tab 2' is flush with the upper surface of the slider body 1'. For assembly, a pair of lateral pivots 22' of the pull tab 2' are received in a pull-tab-holding groove 14' disposed at opposite walls of the pull-tab-receiving groove 12' from a rear end to a center position of the slider body 1', whereupon confronting edges 11' at the pull-tab-holding groove 14' is bent downwardly to prevent the pivots 22' from removing from the pull-tab-holding groove 14', in such a manner that the pull tab 2' can be received in the pull-tab-receiving groove 12'.
As shown in FIGS. 11 and 12, U.S. Pat. No. 2,495,539 discloses a lock slider, for a slide fastener, in which a slider body 1" and a pull tab 2" having a locking pawl are simultaneously molded in an assembled form.
In the slider disclosed in this U.S. Patent, an upper wing 3" of the slider body 1" has a cutout 15" extending from one side edge to a central pull-tab-attaching lug 11" so that the pawl 23" of the pull tab 2" can be inserted. The pull-tab-attaching lug 11" has a pair of lateral projections 14" on which a pair of attaching rings 22" of the pull tab 2" are threaded.
According to the lock slider of the first-named publication, the slider body 1' and the pull tab 2' are molded individually, and then they are assembled to complete the slider, which is laborious and time-consuming. Therefore it is impossible to improve the rate of production. Further, if the pull tab 2' is inverted, the pull tab 2' and a locking pawl 23' would project on the slider body 1' to catch and damage a garment or something around.
According to the lock slider of the second-named publication, the cutout of the upper wing 3" is formed by inserting into the mold a side core having a thickness equal to that of the upper wing 3" during molding. Therefore the cutout 15" of the upper wing 3" is devoid of anything, at a flange side, for guiding the fastener elements, namely, for protecting the corners of the fastener elements. In addition, since the front and rear walls of the cutout 15" of the upper wing 3" have acute edges, the upper surfaces of the fastener elements, especially braids of sewing threads, would tend to be damaged due to the movement of the slider.
Further, partly since one end of the cutout 15" is larger in width than the locking pawl 23", and partly since the front end of the slider body 1" is larger in width than the rear end as a shape of the upper wing 3", smooth guiding of the fastener elements could not be achieved. And since the attaching rings 22" of the pull tab 2" are threaded on the respective lateral projections 14" of the pull-tab-attaching lug 11", stable attachment of the pull tab 2" could not be achieved. Still further, since there is only a side flange 6" bridging upper wing portions about the cutout 15", adequate toughness of the slider is difficult to achieve.